In some inkjet printers, the printheads are part of a discrete assembly separate from detachable ink containers in which ink is held in a block of foam or other capillary material. The ink holding chamber in these foam based ink containers is vented to the atmosphere through an opening in the top of the container. The container vent opening is sealed during storage and shipment to prevent evaporation from the ink chamber. The container vent is sometimes not functional when the container is installed in a printhead assembly, for example when the user fails to remove the vent seal. The printer will not print properly with a malfunctioning container vent.
The same part numbers designate the same or similar parts throughout the figures.